This invention relates to planar air pallet material handling systems and more particularly to an air inlet assembly therefor, including an annular grommet and a rigid air supply nozzle, for pressurizing the air pallet plenum chamber.
Planar air pallet material handling systems have recently been evolved utilizing a rigid backing member for supporting the load (which may comprise a case or carton forming the load itself) and acting in conjunction with an underlying thin flexible sheet bearing perforations over the major surface portion of the same. The planar backing member and the thin flexible sheet (or a bag) define a plenum chamber subjected to pressurized air from an air source. Air escaping through the perforation creates a thin air bearing between the perforated portion of the thin flexible sheet and an underlying imperforate support surface such as the ground, floor, etc. Such system and components are set forth in U.S. Pat. No. 3,948,344 entitled "Low Cost Planar Air Pallet Material Handling System" issuing Apr. 6, 1976. Such systems involve perforations which unrestrictedly open directly to the plenum chamber, air dispersion means, provided within the chamber to insure air flow throughout the chamber when the pallet is under load, since the plenum chamber is totally collapsed with load application and no air can flow thereto, and means for controlling pillowing of the flexible sheet portion defining the chamber to allow jacking of the backing surface and the load sufficiently to permit the pallet to accommodate surface irregularities, both for the load support surface and the backing surface, without ballooning. Additionally, some type of air inlet means must be provided to the chamber for permitting the air under pressure to enter the chamber to effect jacking of the load and for ultimate discharge through the perforations to create the frictionless air film.
Since the function of the pallet is to move the load from place to place, a portable supply of air under pressure must be achieved. In the aforementioned patent, a motor driven air compressor may function as a source of pressurized air being borne by a fork lift truck or the like. Alternatively, a battery powered or gasoline engine powered compressor in a back pack arrangement may be borne by workman with a flexible hose coupling the outlet of the air compressor to the air inlet means leading to the plenum chamber of the air pallet itself.
Difficulties have been encountered in making a detachable connection between the pressurized air source and the air pallet. Additionally, even though the connection may be completed, once pressurization has been attempted or achieved, loss of air may occur at the point of connection, and there may be mechanical separation of the air supply hose or its coupling component at the point of connection to the air pallet and acting to break the air seal.
It is, therefore, a primary object of the present invention to provide an improved air inlet and air dispersion grommet, an air inlet assembly including the grommet, and an improved air pallet incorporating such element for air pallet type material handling systems which function to: elevate the underside of the air pallet slightly to facilitate air dispersion for initial inflation of the plenum chamber; effectively seal the connection between a detachable air supply nozzle and the plenum chamber air inlet opening and mechanically interlock the connection elements.